Density wave like transport anomalies in surface doped Na2IrO3

We report that the surface conductivity of Na2IrO3 crystal is extremely tunable by high energy Ar plasma etching and can be tuned from insulating to metallic with increasing etching time. Temperature dependent electrical transport for the metallic samples show signatures of first order phase transitions which are consistent with charge or spin density wave like phase transitions predicted recently. Additionally, grazing-incidence small-angle x-ray scattering (GISAXS) reveal that the room temperature surface structure of Na2IrO3 does not change after plasma etching.